That Azuki looks to be of the same vintage as my mid-'70s Fuji. I've ridden mine quite a bit more than your old man... and as such, I've also converted it over the past 40+ years into a tourer...
Triple crankset, and six-speed ultra-spaced freewheel were the biggies. The first lighter/better wheelset was put on in '77- (It is on its fourth wheelset since new!) Likewise, the cheap Pletscher rear rack has also been on there since '76 - with the front rack support - and tire savers - and the bar-end shifters... The suspension seatpost was a more-recent acquisition - probably ~30 years ago from Bike Warehouse (now Nashbar)...
Nothing 'wrong' at all about riding an old bike!!!